<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>fill 方法</title>
</head>
<body>
    <script>
        let arr = Array.of(1,2,3,4);
        // 参数1：用来填充的值
        // 参数2：被填充的起始索引
        // 参数3(可选)：被填充的结束索引
        console.log(arr.fill(0,1,2)); //[1,0,3,4]
    </script>
</body>
</html>